The present invention relates to a half duplex radio communication system. More specifically, the invention relates to a channel assignment in a communication network for half duplex radio communication between two terminals through a base station serving as repeater station.
As a system for half duplex radio communication between terminals through the base station, a conventional MCA (Multi-Channel Access) system is well known. In a conventional MCA system, a channel assignment method is employed. A communication channel is assigned upon the initiation of communication, the base station does not manage which terminal equipment effects transmission through the assigned channel, and the terminal equipment to effect transmission is mutually determined between the terminals. After the termination of communication, the base station releases the channel assignment and assigns the corresponding channel for other communication.
Such channel assignments may effectively use of the channels since either one of the terminals uses the assigned channel as long as two communicating terminal equipments are included in the same zone. Details for such a MCA system have been disclosed in NEC Technical Journal, "MCA System", issued by Nippon Electric Company, December, 1982, pages 62.about.65.
Conventional channel assignment methods are, however, not effective, especially when terminals communicating with each other do not exist in the same zone. In such a situation, both a forward channel from the base station to the terminal and a backward channel from the terminal to the base station are assigned at each zone. The two channels are not used simultaneously.